LinuxQuestions.org - Kaudiocreator (slow) vs. K3B (fast) in Slackware 13.37 and 14-RC4

I noticed an odd slowness with kaudiocreator today on my main AMD X2 system. It used to rip commercial audio CDs in < 5 min using kaudiocreator in prior to 13.37. Today was the 1st time I tried ripping a CD with 13.37 using kaudiocreator as I usually use K3B.

Xfce, stock kaudiocreator and K3B, flac, as shipped with Slackware, sequential ripping, best quality preset, 12 track audio CD.

(13.37) 2.6.37.6 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 4800+ (2.4 GHz)
LITE-ON LTR-48125W CDRW
kaudiocreator 29 min 27 s
K3B 2 min 20 s

(14-RC4) 3.2.28 x86_64 Intel Core(TM)2 Duo CPU P9500 @ 2.53 GHz
TSSTcorp DVD+/- RW TS-U633A
kaudiocreator 8 min 10 s
K3B 3 min 26 s

On the AMDX2 numerous entries such as these show up for kaudiocreator but not for K3B. /var/log/messages:

Code:

Sep  9 22:11:15 gandalf kernel: [49484.437963] sr 4:0:1:0: [sr1] Unhandled sense code

Sep  9 22:11:15 gandalf kernel: [49484.437967] sr 4:0:1:0: [sr1]  Result: hostbyte=0x00 driverbyte=0x08

Sep  9 22:11:15 gandalf kernel: [49484.437971] sr 4:0:1:0: [sr1]  Sense Key : 0x3 [current] 

Sep  9 22:11:15 gandalf kernel: [49484.437974] sr 4:0:1:0: [sr1]  ASC=0x11 ASCQ=0x0

Sep  9 22:11:15 gandalf kernel: [49484.437977] sr 4:0:1:0: [sr1] CDB: cdb[0]=0x28: 28 00 00 0

with "Unhandled sense code" being intermittent - not on all tracks read. /var/log/syslog:

Code:

Sep  9 22:11:15 gandalf kernel: [49484.437983] end_request: I/O error, dev sr1, sector 1001772

Sep  9 22:11:15 gandalf kernel: [49484.437986] quiet_error: 4 callbacks suppressed

Sep  9 22:11:15 gandalf kernel: [49484.437988] Buffer I/O error on device sr1, logical block 250443

Sep  9 22:11:15 gandalf kernel: [49484.437992] Buffer I/O error on device sr1, logical block 250444

For Intel laptop and 14-RC4, there are no "Unhandled sense code" errors and just the "Buffer I/O error on device sr1, logical block xxxxx" errors for kaudiocreator. K3B seems errorless. On both systems cpu < 7% during rip, <50% during encode. Flac encoding is fast on both systems. In Slackware14, kaudiocreator is about 3x faster that on 13.37, but still lags well behind K3B.

Thus, the question is, what is wrong with kaudiocreator, or is this normal?

UPDATE: repeated the tests. Times were similar but the AMD64 box did not spit out any "Unhandled sense code" errors.